import java.util.*;

public class HJ26 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String input = in.nextLine(); // 读取输入字符串
        char[] chars = input.toCharArray(); // 将字符串转换为字符数组

        // 提取字母字符及其索引
        List<Character> letters = new ArrayList<>();
        List<Integer> indices = new ArrayList<>();
        for (int i = 0; i < chars.length; i++) {
            if (Character.isLetter(chars[i])) {
                letters.add(chars[i]);
                indices.add(i);
            }
        }

        // 对字母字符进行排序（不区分大小写，保持输入顺序）
        letters.sort(Comparator.comparingInt(Character::toLowerCase));

        // 将排序后的字母字符放回原位置
        for (int i = 0; i < letters.size(); i++) {
            chars[indices.get(i)] = letters.get(i);
        }

        // 输出排序后的字符串
        System.out.println(new String(chars));
    }
}